The Angel Of Khan El Khalili by P. Djèlí Clark

A brisk alternate-history mystery set in a supernatural Cairo, in which a resourceful agent from a government bureau that polices magic is sent into the labyrinthine Khan el-Khalili market to investigate the appearance of a strange angelic being; as she navigates crowded streets, colonial intrigue, and ancient powers, she must unravel who — and what — is behind the phenomenon before the city's fragile peace is shattered.